The White House announced on Thursday that Greg Katsas, one of the top lawyers in the White House, is President Trump's pick for the US Court of Appeals for the DC Circuit.

If confirmed by the Senate, Katsas will serve on the primary federal appeals court for challenges to actions by federal agencies and the executive branch. Last year, the judges heard high-profile fights over the Obama administration's Clean Power Plan and the Consumer Financial Protection Bureau. In July, the court blocked EPA Administrator Scott Pruitt from delaying implementation of regulations concerning methane and other greenhouse gas emissions.

Katsas was widely considered the frontrunner for the seat when the vacancy opened in July. He has served as deputy counsel to the president since Trump took office, and was part of the Justice Department transition team following the election. Before joining the administration he was an appellate lawyer in Washington at the law firm Jones Day — also the former firm of White House counsel Don McGahn, as well as more than a dozen other lawyers who went to work for Trump.

Katsas has stayed out of the limelight during the slew of legal challenges that the administration has already faced over Trump's executive actions on immigration, sanctuary cities, transgender service members in the military, and the rollback of Obama-era federal regulations. Katsas has never been a judge, and absent a judicial record of decisions to delve into, Senate Democrats are likely to press him about his role in these cases.

Katsas, however, only needs 51 votes to join the DC Circuit court, meaning Republicans can confirm him without any Democratic support.

Katsas worked in the Justice Department from 2001 to 2009 under President George W. Bush, including as the head of the Civil Division and as the acting associate attorney general, the number three position at the department. After earning his law degree from Harvard Law School, he clerked for US Supreme Court Justice Clarence Thomas.

Leonard Leo, executive vice president of the Federalist Society, who has advised Trump on judicial nominations, praised the pick.

"I have known Greg Katsas for nearly 30 years and he is among the most honest, fair, humble and intelligent people I have ever met. He understands the awesome responsibility associated with wearing a judicial robe and I have no doubt that he will always place the search for truth, fairness and justice first," Leo said in a statement.

Conservatives have been pleased with Trump's judicial nominees to date — not to mention the administration's steady pace in sending nominees to the Senate for the hundred-plus lower court vacancies. Carrie Severino, chief counsel of the Judicial Crisis Network, said in a statement that Katsas's nomination "is yet another example of President Trump's commitment to nominating qualified, experienced constitutionalists to serve on the courts."

If confirmed, Katsas would not shift the ideological balance of the court, which has a majority of Democrat-nominated active judges; it's the court where Chief Judge Merrick Garland, former president Obama's unsuccessful Supreme Court nominee, serves. Katsas would replace now-retired judge Janice Rogers Brown, who was confirmed under Bush.

Katsas was one of 16 judicial nominations announced on Thursday. Trump will also nominate Ryan Bounds, a federal prosecutor in Oregon, to the Ninth Circuit, and Georgia Court of Appeals Judge Elizabeth Branch to the Eleventh Circuit. Matthew Petersen, a Federal Election Commission commissioner, has been nominated to the US District Court for the District of Columbia.

There are 143 federal court vacancies, and at least 18 more upcoming vacancies have already been announced. There are 31 nominees at various stages of the confirmation process in the US Senate, and Trump thus far has had six judicial nominees confirmed, including Supreme Court Justice Neil Gorsuch.

Zoe Tillman is a legal reporter with BuzzFeed News and is based in Washington, DC.